Methods and Systems for Recovering Liquified Petroleum Gas from Natural Gas

ABSTRACT

A process and system is provided for separating a feed gas stream containing methane, at least one C 2  component, at least one C 3  component, and optionally heavier components, into a volatile gas stream containing a major portion of the methane and at least one C 2  component and a less volatile stream containing a major portion of the at least one C 3  and heavier components. The feed stream is cooled, at least partially condensed, and fed to a fractionation column wherein the feed stream is separated into an overhead vapor stream comprising primarily the lighter components of the feed stream and a bottoms liquid stream comprising primarily the heavier components of the feed stream. The introduction of a reboiler onto the fractionation column assists in removing co-absorbed C 2  and lighter components from the fractionation column bottoms thereby facilitating more efficient operation of a downstream deethanizer column. Addition of residue recycle can further supplement recovery of desired components.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 61/360,753, filed Jul. 1, 2010, which is incorporated byreference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed toward processes and systems forrecovering liquefied petroleum gas (LPG) from a hydrocarbon gas stream,especially a natural gas stream or a refinery gas stream. Particularly,the processes and systems described herein may be utilized to enhanceLPG recovery, particularly when processing higher pressure or leanerfeed streams thereby providing broader applicability compared toprevious processes.

2. Description of the Prior Art

Natural gas comprises primarily methane, but can also include varyingamounts of heavy hydrocarbon components such as ethane, propane, butane,and pentane, for example. It is well known that natural gas streams canbe separated into their respective component parts. Such processesinvolve a combination of chilling, expansion, distillation and/or likeoperations to separate methane and ethane from C₃ and heavierhydrocarbon components. Typically the separation made is of methane andethane from propane and heavier components. If economically desirable,the ethane could also be recovered and similarly, it is desirable inmany instances to further fractionate the recovered C₃ (or alternativelyC₂) and heavier components.

One process that has been devised for separating a natural gas streaminto light and heavy component streams is shown in U.S. Pat. No.5,771,712, incorporated by reference herein its entirety. The '712Patent demonstrates a typical process wherein an overhead stream from adeethanizer is passed into heat exchange with an exit stream from anabsorber to cool the overhead stream from the deethanizer to atemperature at which it is partially liquefied. This partially liquefiedstream is then introduced into the absorber wherein the liquid portionof the stream passes downwardly through the absorber to contact agaseous stream passing upwardly through the absorber. While thisprocessing system has been effective to separate C₂ and lightercomponents from C₃ and heavier components, it is relatively inefficientwhen processing lower pressure feed gas streams. It is also relativelyinefficient when processing rich feed gas streams with respect to theirC₃ and heavier content. It is particularly ineffective when largeamounts of very light gases, such as hydrogen, may be present in thefeed gas stream charged to the process. Hydrogen in gaseous streamsrecovered from refinery operations, which may be desirably separated insuch processes, is not uncommon. While the occurrence of hydrogen insignificant quantities in natural gas is rare, the presence of hydrogenin similar streams from refinery operations is common.

U.S. Pat. No. 6,405,561 discloses a process for recovering C₃ andheavier components from low-pressure natural gas or refinery gasstreams. The '561 patent teaches the improvement of cooling andpartially condensing a deethanizer overhead gas stream to produce adeethanizer liquid stream that is further cooled and directed into anupper portion of a separator/absorber, which separates the inlet feedstream into a liquid bottoms stream comprising primarily C₃ and heaviercomponents and an overhead gas stream comprising primarily C₂ andlighter components. The process of the '561 patent is particularlyeffective for treatment of feed gas streams at lower pressure thatcontain substantial amounts of very light components, including hydrogenthat is often found in refinery applications. The process of the '561patent is also effective for treatment of feed gas streams rich withrespect to recoverable C₃ and heavier components.

However, as feed gas pressure increases, or if feed gas streams withhigher quantities of C₂ and lighter components are used, the process ofthe '561 patent becomes less effective due to co-adsorption of theselighter components in the separator/absorber bottoms stream. As aresult, these lighter components tend to reduce the temperature requiredto partially condense the deethanizer overhead gas stream. Thus, therefrigerant medium used in this condensation operation must be changedfrom propane to a colder, more horsepower-intensive refrigeration media.As a result, the investment in equipment and operating cost is increasedsubstantially.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, there is provided a processfor separating a feed gas stream containing methane, at least one C₂component, and at least one C₃ component into a volatile gas streamcontaining a major portion of the methane and at least one C₂ componentand a less volatile stream containing a major portion of the at leastone C₃ component. The process comprises first cooling the feed gasstream to a temperature sufficient to condense the majority of the atleast one C₃ component in the feed gas stream to produce a cooled feedstream. The cooled feed stream is introduced into a separator vessel toseparate the cooled feed stream into a separator gas stream and aseparator liquid stream. At least a portion of both of the separator gasand liquid streams from the separator vessel is introduced into afractionation column to produce a fractionation column bottoms productand a fractionation column overhead residue gas stream. Thefractionation column bottoms product is introduced into a deethanizertower which produces a deethanizer bottoms stream comprising a majorityof the at least one C₃ component and a deethanizer overhead gas stream.

In another embodiment of the present invention, there is provided aprocess for separating a feed gas stream containing methane, at leastone C₂ component, and at least one C₃ component into a volatile gasstream containing a major portion of the methane and at least one C₂component and a less volatile stream containing a major portion of theat least one C₃ component. The process comprises cooling the feed gasstream to a temperature sufficient to condense the majority of the atleast one C₃ component therein to produce a cooled feed stream. Thecooled feed stream is passed to a fractionation column to produce aliquid fractionation column bottoms product and a fractionation columnoverhead residue gas stream. The fractionation column including areboiler operable to vaporize at least a portion of the fractionationcolumn liquid which is taken from the bottom or near the bottom of thecolumn. The vaporized portion is then reintroduced into thefractionation column. The fractionation column bottoms product isintroduced into a deethanizer tower which produces a deethanizer bottomsstream comprising a majority of the at least one C₃ component and adeethanizer overhead gas stream. The deethanizer overhead gas stream iscooled and at least partially condensed thereby producing a deethanizerliquid reflux stream and a deethanizer residue gas stream. Optionally,the deethanizer residue gas stream is combined with at least a portionof the overhead residue gas stream to form a combined residue gasstream. At least a portion of the combined residue gas stream iscompressed and cooled to produce a residue gas reflux stream. Theresidue gas reflux stream is introduced into the fractionation column.

In a further embodiment of the present invention, there is provided aprocess for separating a feed gas stream containing methane, at leastone C₂ component, and at least one C₃ component into a volatile gasstream containing a major portion of the methane and at least one C₂component and a less volatile stream containing a major portion of theat least one C₃ component. The process comprises cooling the feed gasstream to a temperature sufficient to condense the majority of the atleast one C₃ component in the feed gas stream to produce a cooled feedstream. The cooled feed stream is passed to a fractionation column toproduce a liquid fractionation column bottoms product and afractionation column overhead residue gas stream. The fractionationcolumn bottoms product is introduced into a deethanizer tower, whichproduces a deethanizer bottoms stream comprising a majority of the atleast one C₃ component and a deethanizer overhead gas stream. Thedeethanizer overhead gas stream is cooled and at least partiallycondensed thereby producing a deethanizer liquid reflux stream and adeethanizer residue gas stream. At least a portion of the fractionationcolumn overhead residue gas stream is compressed and cooled to produce aresidue gas reflux stream. The residue gas reflux stream is thenintroduced into the fractionation column.

In yet another embodiment of the present invention, there is provided asystem for separating a feed gas stream containing methane, at least oneC₂ component, and at least one C₃ component into a volatile gas streamcontaining a major portion of the methane and at least one C₂ componentand a less volatile stream containing a major portion of the at leastone C₃ component. The system comprises a feed stream heat exchangerconfigured to cool the feed gas stream to a temperature sufficient tocondense the majority of the at least one C₃ component in the feed gasstream to produce a cooled feed stream. A separator vessel is locateddownstream from the first heat exchanger and configured to separate thecooled feed stream into a separator gas stream and a separator liquidstream. A fractionation column is located downstream from the separatorvessel and configured to receive at least a portion of both theseparator gas and liquid streams and produce a fractionation columnbottoms product and a fractionation column overhead residue gas stream.A deethanizer tower is located downstream from the separator vessel andconfigured to receive at least a portion of the fractionation columnbottoms product and to produce a deethanizer bottoms stream comprising amajority of the at least one C₃ component and a deethanizer overhead gasstream.

In still another embodiment of the present invention, there is provideda system for separating a feed gas stream containing methane, at leastone C₂ component, and at least one C₃ component into a volatile gasstream containing a major portion of the methane and at least one C₂component and a less volatile stream containing a major portion of theat least one C₃ component. The system comprises a feed stream heatexchanger configured to cool the feed gas stream to a temperaturesufficient to condense the majority of the at least one C₃ componenttherein to produce a cooled feed stream. A fractionation column islocated downstream from the feed stream heat exchanger and is configuredto receive the cooled feed stream and produce a fractionation columnbottoms product and a fractionation column overhead residue gas stream.The fractionation column includes a reboiler configured to vaporize atleast a portion of the fractionation column liquid and reintroduce thevaporized fractionation column liquid back into the fractionationcolumn. A deethanizer tower is located downstream from the fractionationcolumn and configured to receive at least another portion of thefractionation column bottoms product and produce a deethanizer bottomsstream comprising a majority of the at least one C₃ component and adeethanizer overhead gas stream. A deethanizer heat exchanger isprovided and configured to receive and cool the deethanizer overhead gasstream. A deethanizer separation vessel is located downstream from thedeethanizer heat exchanger and is configured to separate the cooleddeethanizer overhead gas stream into a deethanizer liquid reflux streamand a deethanizer residue gas stream. Optionally, the system furtherincludes a conduit configured to merge at least a portion of thedeethanizer residue gas stream with at least a portion of thefractionation column overhead residue gas stream to form a combinedresidue gas stream. A residue gas heat exchanger is provided andconfigured to condense at least a portion of the combined residue streamto form a residue gas reflux stream. Conduit is configured to deliver atleast a portion of the residue gas reflux stream from the gascondensation unit to the fractionation column.

In even a further embodiment, there is provided a system for separatinga feed gas stream containing methane, at least one C₂ component, and atleast one C₃ component into a volatile gas stream containing a majorportion of the methane and at least one C₂ component and a less volatilestream containing a major portion of the at least one C₃ component. Thesystem comprises a feed stream heat exchanger configured to cool thefeed gas stream to a temperature sufficient to condense the majority ofthe at least one C₃ component in the feed gas stream to produce a cooledfeed stream. A fractionation column is located downstream from the heatexchanger and is configured to receive the cooled feed stream andproduce a fractionation column bottoms product and a fractionationcolumn overhead residue gas stream. A deethanizer tower is locateddownstream from the fractionation column and configured to receive atleast a portion of the fractionation column bottoms product and producea deethanizer bottoms stream comprising a majority of the at least oneC₃ component and a deethanizer overhead gas stream. A deethanizer heatexchanger is provided and configured to receive and cool the deethanizeroverhead gas stream. A deethanizer separation vessel is provided andconfigured to separate the cooled deethanizer overhead gas stream into adeethanizer liquid reflux stream and a deethanizer residue gas stream.Conduit is provided and configured to deliver at least a portion of thedeethanizer liquid reflux stream to the fractionation column. A residuegas heat exchanger is provided and configured to condense at least aportion of the fractionation column overhead residue gas stream. Conduitis provided and configured to deliver at least a portion of thecondensed fractionation column overhead residue gas stream to thefractionation column.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a process according to one embodimentof the present invention; and

FIG. 2 is a schematic diagram of a process according to anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning to FIG. 1, an embodiment of the present invention is shown thatis particularly adapted for the recovery of C₃ and heavier componentsfrom a hydrocarbon-containing gas stream, such as a natural gas orrefinery gas stream. In particular embodiments, the inlet feed gasstream 10 comprises methane, at least one C₂ component, at least one C₃component, and optionally heavier components. In still otherembodiments, inlet feed gas stream 10 comprises methane as thepredominant component, with C₂, C₃, and heavier components being presentin lesser amounts. In refinery applications, the feed may also containsignificant quantities of lighter components such as hydrogen.Particularly, in certain applications, the feed stream may comprise asmuch as 10%, or even as much as 50%, hydrogen.

The present invention exhibits the flexibility to accommodate a widevariety of feed pressures. In one embodiment, the feed stream 10 can besupplied at a pressure of at least 300 psi, or particularly, betweenabout 350 psi to about 700 psi. Typically, feed stream 10 will besupplied at a temperature that is above the condensation point for theC₃ components present therein; therefore, feed stream will need to becooled in order to condense these components. In this embodiment, feedgas stream 10 is passed through a heat exchanger 12 where it is cooledto a temperature sufficient to condense the majority of the at least oneC₃ component in the feed gas stream to produce a cooled gas feed stream.Note, the use of the word “gas” in the term “cooled gas feed stream”should not be taken as implying that the entirety of the stream ispresent in the gaseous state. Certain components, particularly theheavier components may be present as liquids. The cooling streams usedin heat exchanger 12 are discussed in greater detail below. It will beunderstood that the heat exchange function shown schematically in heatexchanger 12 may be accomplished in a single or a plurality of heatexchange vessels.

The cooled inlet gas is passed via a line or conduit 14 to a separationvessel 16 where it is separated into a vapor stream 18 and a bottomsstream 20. Vapor stream 18 is directed toward an expander 22 to reducethe pressure of and further cool the stream. The expanded vapor streamis passed via a line 24 to a fractionation column 26 containing one ormore theoretical stages of mass transfer. In certain embodiments, thefractionation column 26 is a conventional distillation column containinga plurality of vertically spaced trays, one or more packed beds, or somecombination of trays and packing.

The bottoms stream 20 recovered from separator vessel 16 containsprimarily C₃ and heavier components, although the bottoms stream 20 willalso contain quantities of lighter materials. As explained furtherbelow, ultimately these lighter components will be separated from the C₃and heavier components in subsequent processing steps. In order tomaximize the efficiency of those subsequent processing steps, thepresent embodiment seeks to control the levels of C₂ and lightercomponents contained in the liquid, predominantly C₃ stream that will befurther processed. Thus, bottoms stream 20 is also passed tofractionation column 26. Generally, bottoms stream 20 is introduced intofractionation column 26 below the introduction point for the expandedvapor stream carried by line 24, although the arrangement of theintroduction points for the various streams fed to fractionation column26 can be varied as deemed appropriate. This step of introducing bottomsstream 20 into fractionation column 26 provides an opportunity for thelighter materials co-absorbed in liquid bottoms stream 20 to beseparated therefrom. Fractionation column 26 is equipped with anoptional reboiler 28 to assist with separation of the C₂ and lightercomponents from the bottoms of the fractionation column. A portion ofthe fractionation column liquids taken from the bottom or near thebottom of column 26 are directed to reboiler 28 and at least partiallyvaporized and then reintroduced into the fractionation column 26.Accordingly, as the liquid stream exiting fractionation column 26contains fewer C₂ or lighter components, it has higher condensationtemperature than the stream 20. This permits a propane refrigerant, orsimilar refrigerant, to be used to condense the overhead stream from adeethanizer 36, which is discussed in greater detail below. Otherwise,if the bottoms product from fractionation column 26 contained a higherlevel of C₂ or lighter components, a colder and therefore more expensiverefrigeration system would need to be employed.

In fractionation column 26, a liquid bottoms stream comprising primarilyC₃ and heavier components plus some light components is recovered via aline 30 and a pump 32 and pumped via a line 34 to heat exchanger 12where it is used to cool the inlet gas stream in line 10. The stream inline 34 is then passed to a deethanizer 36. In deethanizer 36 the streamfrom line 34 is separated by conventional distillation techniques aswell known to the art for deethanizers into an overhead vapor stream 38and a bottoms stream 40. Deethanizer 36 also comprises a conventionalreboiler 42. The stream recovered from deethanizer 36 through line 40comprises primarily C₃ and heavier components. An overhead stream isrecovered from the deethanizer via line 38, which is rich in C₂ andlighter components and is passed to a heat exchanger 44 where it ispartially condensed and then through a line 46 to a separator 48. Fromseparator 48, a liquid stream is withdrawn via a line 50 and passed to apump 52 from which a portion of the liquid stream is passed via a line54 into an upper portion of deethanizer 36 as a reflux. The vapor streamrecovered from separator 48 is passed via a line 56.

Deethanizer 36 is maintained at a higher pressure than fractionationcolumn 26. The increased pressure for deethanizer 36 is supplied by pump32 and maintained by a valve 57 disposed in line 56. In certainembodiments, the pressure in deethanizer 36 is at least 25 psi, or atleast 100 psi, or at least 200 psi greater than the pressure infractionation column 26.

A second portion of the liquid stream from separator 48 is passed via aline 58, through a heat exchanger 60, and into an upper portion offractionation column 26. An overhead vapor stream recovered from theupper portion of fractionation column 26 is passed via a line 62,through heat exchanger 66 and then combined with the stream in line 56.It is noted that the stream carried by line 56 is flashed across valve57. The combined stream contains a residue gas that comprises a majorportion of the C₂ and lighter components from the inlet gas feed stream.This stream is passed via line 64 through heat exchanger 12 so as toprovide cooling for feed stream 10. Alternatively, stream 56 and stream62 can be passed separately through heat exchanger 12 such that stream56, which contains a significant quantity of C₂ components, would beavailable for internal use thus reducing the C₂ content of the residuegas.

The cooling to heat exchanger 12 provided by the materials carried bylines 34 and 64 can be supplemented by a refrigerant, such as propane,supplied to heat exchanger 12 by line 76. Next, the residue gas carriedby line 64 is passed through a compressor 66. The residue gas exitscompressor 66 via line 68. Optionally, a portion of the residue gascarried by line 68 is passed via a line 70 to a heat exchanger 72 whereit is cooled and condensed. In the embodiment illustrated, the chilledportion of residue gas exiting heat exchanger 72 is refluxed to the topof fractionation column 26. The other portion of residue gas from line68 is withdrawn from the system via line 74. In those embodiments inwhich streams 56 and 62 are not combined and an additional reflux isdesired for column 26, a portion of the contents of stream 62 arecompressed, condensed and refluxed to the column.

In an illustrative embodiment of the process shown in FIG. 1, adehydrated gas stream is charged to the process at 340 psia and 114° F.The gas stream is cooled in heat exchanger 12 to a temperature of −66° Fand 330 psia and charged to separation vessel 16. In separation vessel16, gaseous overhead stream 18 is produced and passed through expander22 and is carried by line 24 at −99° F. and 150 psia to fractionationcolumn 26. The liquid stream recovered via line 20 at −1.5° F. and 145psia and directed through pump 32 where its pressure is increased to 360psia. The stream carried by line 34 is used to provide refrigeration toheat exchanger 12 and then directed to deethanizer 36 at a temperatureof 74° F. and 355 psia.

In deethanizer 36, a bottoms liquid stream composed primarily of C₃ andheavier components is recovered via a line 40 at a temperature of 173°F. at 350 psia. The vapor stream recovered via line 56 is at atemperature of 24° F. at 335 psia. In the current simulation, the vaporstream recovered via line 56 was withdrawn from the system and used asfuel gas. However, as illustrated in FIG. 1, this stream can be flashedacross valve 57 and combined with the gas carried by line 62. A liquidreflux stream carried by line 58 is withdrawn from the deethanizer at atemperature of 24° F. and 335 psia. This stream is cooled, expanded, andrefluxed to fractionation column 26 at −111° F. and 145 psia.

The overhead vapor from fractionation column 26 carried by line 62 is ata temperature of −117° F. and a pressure of 140 psia and is heatexchanged with the stream carried by line 58 and emerges from heatexchanger 60 at −99°F. and 135 psia and directed to heat exchanger 12via line 64. This residue gas stream exits heat exchanger 12 at 95° F.and 125 psia and is directed toward compressor 66 (in this simulation aseries of compressor stages with intercooling) where it is boosted to1265 psia and its temperature raised to 115° F. A portion of thiscompressed stream is withdrawn via line 70, cooled and condensed by heatexchanger 72 and refluxed to fractionation column 26 at a temperature of−112° F. and pressure of 1255 psia.

While specific temperatures have been referred to in connection with theembodiment illustrated in FIG. 1, it should be understood that a widerange of temperature and pressure variations are possible within thescope of the present invention. Such temperature and pressure variationsare readily determined by those skilled in the art based upon thecomposition of the specific feed streams, the desired recoveries and thelike within the scope of the processes disclosed above.

FIG. 2 illustrates another embodiment of a process in accordance withthe present invention. Note, when applicable, the same referencenumerals used in the description of FIG. 1 have been used to identifycomparable lines or equipment. In the process of FIG. 2, the inlet gasstream is charged to the process via a line 10. The inlet feed gas iscooled in a heat exchanger 12 and thereafter passed via a line 14 to aheat exchanger 15 where it is further cooled to a selected temperatureand passed via line 17 to a fractionation column 26 containing one ormore theoretical stages of mass transfer. Fractionation column 26 isequipped with a reboiler 28 to assist with separation of the C₂ andlighter components from the bottoms of the fractionation column. Aportion of the tower liquid from fractionation column 26 is directed toreboiler 28 and at least partially vaporized and then reintroduced intothe bottom of fractionation column 26.

In fractionation column 26, a liquid bottoms product comprisingprimarily C₃ and heavier components plus some light components isrecovered via a line 30 and a pump 32 and pumped via a line 34 to heatexchanger 12 where it is used to cool the inlet gas stream in line 10.The stream in line 34 is then passed via to a deethanizer 36. Indeethanizer 32 the stream from line 34 is separated by conventionaldistillation techniques into an overhead vapor stream 38 and a bottomsstream 40. A conventional reboiler 42 is shown for with-drawing aportion of the deethanizer tower liquid, at least partially vaporizingthe withdrawn portion, and returning the at least partially vaporizedstream back to deethanizer 36. The stream recovered from deethanizer 36through line 40 comprises primarily C₃ and heavier components. Anoverhead stream is recovered from the deethanizer via line 38, which isrich in C₂ and lighter components and is passed to a heat exchanger 44where it is at least partially condensed and then through a line 46 to aseparator 48. From separator 48, a liquid stream is withdrawn via a line50 and passed to a pump 52 from which a portion of the liquid stream ispassed via a line 54 into an upper portion of deethanizer 36 as areflux. The vapor stream recovered from separator 48 is passed via aline 56 and through an expansion valve 57. The vapor stream is thencombined with the residue gas from line 62 and directed toward acompressor 66 via line 64.

A second portion of the liquid stream from separator 48 is passed via aline 58 and a heat exchanger 60 into an upper portion of fractionationcolumn 26. An overhead vapor stream recovered from the upper portion offractionation column 26 is passed via a line 62 through heat exchanger60 to combination with the stream in line 26. The combined streamcarried by line 64 contains a major portion of the C₂ and lightercomponents from the inlet gas feed stream. As noted above, the stream inline 64 is compressed by compressor 66 and passed into line 68. Aportion of the compressed residue gas carried by line 68 is passed via aline 70 to a heat exchanger 72 where it is cooled and condensed. In theembodiment illustrated, the condensed portion of residue gas exitingheat exchanger 72 is refluxed to the top of fractionation column 26. Theother portion of residue gas from line 68 is withdrawn from the systemvia line 74.

It is noted that, as discussed above with respect to FIG. 1, in certainembodiments, streams 56 and 62 may be kept separate. When an additionalreflux is desired for column 26, a slip stream of the material carriedby line 62 can be compressed, condensed, and refluxed to the column. Itis also noted that for any embodiment discussed above, it is within thescope of the present invention for the residue gas reflux carried byline 70 to be used without equipping fractionation column 26 with areboiler 28.

While the present invention has been described by reference to certainof its preferred embodiments, it is respectfully pointed out that theembodiments described are illustrative rather than limiting in natureand that many variations and modifications are possible within the scopeof the present invention.

1. A process for separating a feed gas stream containing methane, atleast one C₂ component, and at least one C₃ component into a volatilegas stream containing a major portion of the methane and at least one C₂component and a less volatile stream containing a major portion of theat least one C₃ component, the process comprising: a) cooling the feedgas stream to a temperature sufficient to condense the majority of theat least one C₃ component in the feed gas stream to produce a cooledfeed stream; b) introducing the cooled feed stream into a separatorvessel to separate the cooled feed stream into a separator gas streamand a separator liquid stream; c) introducing at least a portion of bothof the separator gas and liquid streams from the separator vessel into afractionation column to produce a fractionation column bottoms productand a fractionation column overhead residue gas stream; d) introducingthe fractionation column bottoms product into a deethanizer tower andproducing a deethanizer bottoms stream comprising a majority of the atleast one C₃ component and a deethanizer overhead gas stream; e) coolingand at least partially condensing the deethanizer overhead gas streamthereby producing a deethanizer liquid reflux stream and a deethanizerresidue gas stream; and f) introducing at least a portion of thedeethanizer liquid reflux stream into the fractionation column.
 2. Theprocess according to claim 1, wherein the fractionation column furtherincludes a reboiler operable to vaporize at least a portion of afractionation column liquid, the vaporized fractionation column liquidbeing reintroduced into the fractionation column.
 3. The processaccording to claim 1, further comprising: g) combining the fractionationcolumn overhead residue gas stream with at least a portion of thedeethanizer residue gas stream to form a combined residue gas stream; h)compressing and cooling at least a portion of the combined residue gasstream to produce a residue gas reflux stream; and i) introducing theresidue gas reflux stream into the fractionation column.
 4. The processaccording to claim 1, wherein the process further comprises: g)compressing and cooling at least a portion of the fractionation columnoverhead residue gas stream to produce a residue gas reflux stream; andh) introducing the residue gas reflux stream into the fractionationcolumn.
 5. A process for separating a feed gas stream containingmethane, at least one C2 component, and at least one C3 component into avolatile gas stream containing a major portion of the methane and atleast one C2 component and a less volatile stream containing a majorportion of the at least one C3 component, the process comprising: a)cooling the feed gas stream to a temperature sufficient to condense themajority of the at least one C3 component in the feed gas stream toproduce a cooled feed stream; b) passing the cooled feed stream to afractionation column to produce a liquid fractionation column bottomsproduct and a fractionation column overhead residue gas stream, thefractionation column including a reboiler operable to vaporize at leasta portion of a fractionation column liquid, the vaporized fractionationcolumn liquid being reintroduced into the fractionation column; c)introducing the fractionation column bottoms product into a deethanizertower and producing a deethanizer bottoms stream comprising a majorityof the at least one C₃ component and a deethanizer overhead gas stream;d) cooling and at least partially condensing the deethanizer overheadgas stream thereby producing a deethanizer liquid reflux stream and adeethanizer residue gas stream; and e) introducing at least a portion ofthe deethanizer liquid reflux stream into the fractionation column. 6.The process according to claim 5, wherein the process further comprises:f) compressing and cooling at least a portion of the fractionationcolumn overhead residue gas stream to produce a residue gas refluxstream; and g) introducing the residue gas reflux stream into thefractionation column.
 7. The process according to claim 6, wherein priorto step (b) introducing the cooled feed stream into a separator vesselto separate the cooled feed stream into a separator gas stream and aseparator liquid stream.
 8. The process according to claim 6, whereinthe process further comprises, prior to step (f), combining at least aportion of the deethanizer residue gas stream with the at least aportion of the fractionation column overhead gas residue stream.
 9. Theprocess according to claim 9, wherein prior to step (b) introducing thecooled feed stream into a separator vessel to separate the cooled feedstream into a separator gas stream and a separator liquid stream.
 10. Aprocess for separating a feed gas stream containing methane, at leastone C₂ component, and at least one C₃ component into a volatile gasstream containing a major portion of the methane and at least one C₂component and a less volatile stream containing a major portion of theat least one C₃ component, the process comprising: a) cooling the feedgas stream to a temperature sufficient to condense the majority of theat least one C₃ component in the feed gas stream to produce a cooledfeed stream; b) passing the cooled feed stream to a fractionation columnto produce a liquid fractionation column bottoms product and afractionation column overhead residue gas stream, c) introducing thefractionation column bottoms product into a deethanizer tower andproducing a deethanizer bottoms stream comprising a majority of the atleast one C₃ component and a deethanizer overhead gas stream; d) coolingand at least partially condensing the deethanizer overhead gas streamthereby producing a deethanizer liquid reflux stream and a deethanizerresidue gas stream; e) introducing at least a portion of the deethanizerliquid reflux stream into the fractionation column; f) compressing andcooling at least a portion of the fractionation column over-head residuegas stream to produce a residue gas reflux stream; and g) introducingthe residue gas reflux stream into the fractionation column.
 11. Theprocess according to claim 10, wherein prior to step (f), at least aportion of the deethanizer overhead gas stream is combined with thefractionation column overhead residue gas stream.
 12. A system forseparating a feed gas stream containing methane, at least one C₂component, and at least one C₃ component into a volatile gas streamcontaining a major portion of the methane and at least one C₂ componentand a less volatile stream containing a major portion of the at leastone C₃ component, the system comprising: a) a feed stream heat exchangerconfigured to cool the feed gas stream to a temperature sufficient tocondense the majority of the at least one C₃ component in the feed gasstream to produce a cooled feed stream; b) a separator vessel locateddownstream from the first heat exchanger and configured to separate thecooled feed stream into a separator gas stream and a separator liquidstream; c) a fractionation column located downstream from the separatorvessel and configured to receive at least a portion of both theseparator gas and liquid streams and produce a fractionation columnbottoms product and a fractionation column overhead residue gas stream;d) a deethanizer tower located downstream from the separator vessel andconfigured to receive at least a portion of the fractionation columnbottoms product and produce a deethanizer bottoms stream comprising amajority of the at least one C₃ component and a deethanizer overhead gasstream; e) a deethanizer heat exchanger configured to receive and coolthe deethanizer overhead gas stream; and f) a deethanizer separationvessel configured to separate the cooled deethanizer overhead gas streaminto a deethanizer liquid reflux stream and a deethanizer residue gasstream.
 13. The system according to claim 12, wherein the fractionationcolumn further includes a reboiler configured to vaporize at least aportion of a fractionation column liquid and reintroduce the vaporizedfractionation column liquid back into the fractionation column.
 14. Thesystem according to claim 12, further comprising: g) conduit configuredto merge at least a portion of the deethanizer residue gas stream withat least a portion of the fractionation column overhead residue gasstream to form a combined residue gas stream; h) a residue gas heatexchanger configured to receive at least a portion of the combinedresidue gas stream and to produce a residue gas reflux stream; and i)conduit configured to deliver at least a portion of the residue gasreflux stream from the residue gas heat exchanger to the fractionationcolumn.
 15. The system according to claim 12, further comprising: g) acompressor located upstream from the residue gas heat exchanger andconfigured to compress the combined residue gas stream.
 16. A system forseparating a feed gas stream containing methane, at least one C₂component, and at least one C₃ component into a volatile gas streamcontaining a major portion of the methane and at least one C₂ componentand a less volatile stream containing a major portion of the at leastone C₃ component, the system comprising: a) a feed stream heat exchangerconfigured to cool the feed gas stream to a temperature sufficient tocondense the majority of the at least one C₃ component in the feed gasstream to produce a cooled feed stream; b) a fractionation columnconfigured to receive the cooled feed stream and produce a fractionationcolumn bottoms product and a fractionation column overhead residue gasstream, the fractionation column including a reboiler configured tovaporize at least a portion of a fractionation column liquid andreintroduce the vaporized fractionation column liquid back into thefractionation column; c) a deethanizer tower located downstream from thefractionation column and configured to receive at least another portionof the fractionation column bottoms product and produce a deethanizerbottoms stream comprising a majority of the at least one C₃ componentand a deethanizer overhead gas stream; d) a deethanizer heat exchangerconfigured to receive and cool the deethanizer overhead gas stream; ande) a deethanizer separation vessel configured to separate the cooleddeethanizer overhead gas stream into a deethanizer liquid reflux streamand a deethanizer residue gas stream.
 17. The system according to claim16, the system further comprising: f) a residue gas heat exchangerconfigured to condense at least a portion of the fractionation columnoverhead residue gas stream to form a residue gas reflux stream; and g)conduit configured to deliver at least a portion of the residue gasreflux stream from the residue gas heat exchanger to the fractionationcolumn.
 18. The system according to claim 16, further comprising: f) acompressor located upstream from the residue gas heat exchanger andconfigured to compress the fractionation column overhead residue gasstream.
 19. The system according to claim 16, further comprising: f)conduit configured to merge at least a portion of the deethanizerresidue gas stream with at least the fractionation column overheadresidue gas stream to form a combined residue gas stream.
 20. A systemfor separating a feed gas stream containing methane, at least one C₂component, and at least one C₃ component into a volatile gas streamcontaining a major portion of the methane and at least one C₂ componentand a less volatile stream containing a major portion of the at leastone C₃ component, the system comprising: a) a feed stream heat exchangerconfigured to cool the feed gas stream to a temperature sufficient tocondense the majority of the at least one C₃ component in the feed gasstream to produce a cooled feed stream; b) a fractionation columnconfigured to receive the cooled feed stream and produce a fractionationcolumn bottoms product and a fractionation column overhead residue gasstream; c) a deethanizer tower located downstream from the fractionationcolumn and configured to receive at least a portion of the fractionationcolumn bottoms product and produce a deethanizer bottoms streamcomprising a majority of the at least one C₃ component and a deethanizeroverhead gas stream; d) a deethanizer heat exchanger configured toreceive and cool the deethanizer overhead gas stream; e) a deethanizerseparation vessel configured to separate the cooled deethanizer overheadgas stream into a deethanizer liquid reflux stream and a deethanizerresidue gas stream; f) conduit configured to deliver at least a portionof the deethanizer liquid reflux stream to the fractionation column; g)a residue gas heat exchanger configured to condense at least a portionof the fractionation column overhead residue gas stream; and h) conduitconfigured to deliver at least a portion of the condensed fractionationcolumn overhead residue gas stream to the fractionation column.
 21. Thesystem according to claim 20, further comprising: i) conduit configuredto merge at least a portion of the deethanizer residue gas stream withat least the fractionation column overhead residue gas stream to form acombined residue gas stream.